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84321I - Block Diagram
84321I - Pinout


260MHz, Crystal-to-3.3V Differential LVPECL Frequency Synthesizer

Alternative Products
NOTICE - The following device(s) are recommended alternatives:

The 84321I is a general purpose, dual output Crystal-to- 3.3V Differential LVPECL High Frequency Synthesizer The 84321I has a selectable TEST_CLK or crystal inputs. The VCO operates at a frequency range of 620MHz to 780MHz. The VCO frequency is programmed in steps equal to the value of the input reference or crystal frequency. The VCO and output frequency can be programmed using the serial or parallel interfaces to the configuration logic. The low phase noise characteristics of the 84321I make it an ideal clock source for Fibre Channel 1, Fibre Channel 2, 10 Gigabit Fibre Channel, Gigabit Ethernet and 10 Gigabit Ethernet applications.


  • Dual differential 3.3V LVPECL outputs
  • Selectable crystal oscillator interface or LVCMOS/LVTTL TEST_CLK
  • Output frequency range: 103.3MHz to 260MHz
  • Crystal input frequency range: 14MHz to 40MHz
  • VCO range: 620MHz to 780MHz
  • Parallel or serial interface for programming counter and output dividers
  • RMS period jitter: 3ps (typical)
  • RMS phase jitter at 155.52MHz, using a 38.88MHz crystal (12kHz to 20MHz): 2.5ps (typical)
    Phase noise: 155.52MHz
    Offset                    Noise Power
      100Hz …………….. -84.1 dBc/Hz
        1kHz …………… -109.8 dBc/Hz
      10kHz …………… -126.3 dBc/Hz
    100kHz …………… -128.7 dBc/Hz
  • 3.3V supply voltage
  • -40°C to 85°C ambient operating temperature
  • Available in lead-free (RoHS 6) package

Product Specification

Outputs (#)Output TypeOutput Freq Range (MHz)Input Freq (MHz)Inputs (#)Input TypeOutput Banks (#)Core Voltage (V)Output Voltage (V)
2LVPECL103.300000 - 260.00000014.000000 - 40.0000001Crystal13.33.3

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
84321AYILFLast Time BuyPRG32TQFP32IYesTrayCheck Availability
84321AYILFTLast Time BuyPRG32TQFP32IYesReelCheck Availability


Technical Documentation

Title Type Format File Size Datesort icon
Datasheets & Errata
84321I Final Data Sheet PDN Datasheet PDF 258 KB Nov 5, 2015
Apps Notes & White Papers
AN-828 Termination - LVPECL Application Note PDF 229 KB Jul 5, 2016
AN-831 The Crystal Load curve Application Note PDF 308 KB Sep 22, 2014
AN-844 Termination - AC Coupling Clock Receivers Application Note PDF 82 KB May 13, 2014
show all (18)
AN-842 Thermal Considerations in Package Design and Selection Application Note PDF 403 KB May 12, 2014
AN-840 Jitter Specifications for Timing Signals Application Note PDF 349 KB May 8, 2014
AN-803 Crystal Timing Budget and Accuracy for IDT Timing Clock Products Application Note PDF 44 KB May 8, 2014
AN-839 RMS Phase Jitter Application Note PDF 149 KB May 7, 2014
AN-838 Peak-to-Peak Jitter Calculations Application Note PDF 32 KB May 7, 2014
AN-837 Overdriving the Crystal Interface Application Note PDF 50 KB May 6, 2014
AN-834 Hot-Swap Recommendations Application Note PDF 67 KB May 6, 2014
AN-832 Timing Budget and Accuracy Application Note PDF 48 KB May 6, 2014
AN-830 Quartz Crystal Drive Level Application Note PDF 59 KB May 5, 2014
AN-827 Application Relevance of Clock Jitter Application Note PDF 1.06 MB Apr 24, 2014
AN-815 Understanding Jitter Units Application Note PDF 476 KB Apr 24, 2014
AN-802 Crystal-Measuring Oscillator Negative Resistance Application Note PDF 52 KB Mar 12, 2014
AN-806 Power Supply Noise Rejection Application Note PDF 353 KB Jan 15, 2014
AN-805 Recommended Ferrite Beads Application Note PDF 38 KB Jan 15, 2014
AN-801 Crystal-High Drive Level Application Note PDF 109 KB Jan 15, 2014
PDN# : CQ-15-05 Market Declined Quarterly PDN Product Discontinuation Notice PDF 623 KB Oct 29, 2015
PCN# : TB1504-01R1 Qty per Reel Standardization for Selective Packages Product Change Notice PDF 95 KB Oct 22, 2015
PCN# : TB1504-01 Qty per Reel Standardization for Selective Packages Product Change Notice PDF 50 KB Jul 21, 2015
show all (5)
PCN#: A1309-03 Additional Assembly Sources Product Change Notice PDF 398 KB Oct 21, 2013
PCN# : TB1303-01 Change of Carrier Tape for TQFP-32, TQFP-48 Product Change Notice PDF 472 KB Mar 31, 2013